Lesson 6 - General Effects of Resistance Training on Skeletal Muscle

Question 1

What causes strength to increase due to resistance training?

Answer 1

• changes in the nervous system and increases in muscle mass

Question 2

How does the nervous system change in response to resistance training?

Answer 2

• increased neural drive
• decreased inhibition
• increased spinal motor neuron excitability
• improved motor unit recruitment and discharge rate (more efficient)
• improved coordination of motor units

Question 3

When do most neural adaptations occur and contribute to most of strength gain?

Answer 3

4-6 weeks

Question 4

What is hypertrophy?

Answer 4

increase in muscle fiber cross-sectional area making more contractile proteins per fiber

Question 5

What is the primary mean of increased strength with long-term resistance training?

Answer 5

hypertrophy

Question 6

How long does it take for hypertrophy to occur with a high intensity program?

Answer 6

3 weeks

Question 7

Which muscle fiber type increases in size?

Answer 7

both type 1 and 2, with type 2 having greater capacity for change

Question 8

What is the reason for the increase in muscle size/hypertrophy?

Answer 8

addition of sarcomeres

Question 9

What is hyperplasia?

Answer 9

an increase in the number of muscle fibers in a given muscle

Question 10

Does hyperplasia occur in humans?

Answer 10

not enough evidence supporting or negating

Question 11

What type of fiber shift is typically seen from resistance training?

Answer 11

type 2x to type 2a due to change in myosin isoform and reduced ATPase activity for better efficiency

fast to slow

Question 12

What is mechanotranduction?

Answer 12

process by which high mechanical stress is translated to chemical signals that ultimately lead to increased production of contractile protein and muscle growth

Question 13

What does mechanotransduction rely on?

Answer 13

activation on mechanoreceptors that mediate mammalian target of rapamycin complex 1 and other aerobic pathways

Question 14

What muscle fiber has the most satellite cells?

Answer 14

type 2 fibers

Question 15

What does the activation of satellite cells do with hypertrophy?

Answer 15

donate their nuclei to muscle fibers and increase number of nuclei per fiber helping in muscle repair

Question 16

What stimulates satellite cells?

Answer 16

muscle damage

Question 17

What percentage of 1RM can induce hypertrophy if performed to fatigue?

Answer 17

30% 1RM

Question 18

What does low load reps to fatigue trigger?

Answer 18

• increased recruitment of larger muscle fibers
• increased accumulation of metabolites due to shift to anaerobic metabolism, stimulate hypertrophy
• increased production of IGF-1 and growth hormone

Question 19

How long of rest should you take for hypertrophy?

Answer 19

short rest

Question 20

How does decreasing inter-set intervals (rest time) increase metabolic stress and hypertrophy?

Answer 20

decreases training volume and mechanical load

Question 21

What are the 4 main mechanisms of hypertrophy?

Answer 21

• mechanotransduction
• activation of satellite cells
• hypertrophy by induced metabolic stress
• modulation of mechanical load and metabolic stress

Question 22

What are the primary hormones that affect adaptation to resistance exercise?

Answer 22

testosterone and growth hormone

Question 23

What does testosterone do?

Answer 23

• amplify growth hormone and insulin like growth factor 1 (IGF-1) release and action
• increases muscle force production by interacting with nervous system

Question 24

What do repeated session of resistance training do to the temporary increase in testosterone during exercise?

Answer 24

increases frequency and amplitude

Question 25

What are the most effective exercises at increasing testosterone?

Answer 25

- high intensity with large muscle groups (deadlift and squat 85-90%) - high volume exercise with little rest between

Question 26

What does long-term resistance training do to men resting testosterone levels?

Answer 26

raise it

Question 27

What is DOMS?

Answer 27

delayed onset muscle soreness

Question 28

When does DOMS tend to appear?

Answer 28

24-48 hours after strenuous exercise

Question 29

Why does DOMS occur?

Answer 29

- small tears in muscle - osmotic pressure changes - muscle spasms - overstretching/tearing connective tissue - acute inflammation - altered calcium regulation

Question 30

Which movement produces DOMS the most?

Answer 30

eccentric movements

Question 31

What is the repeated bout effect regarding DOMS?

Answer 31

- performing new exercise produces DOMS - performing the same exercise rarely produces DOMS

Question 32

What are muscle cramps related to exercise?

Answer 32

- painful, spasmodic involuntary contractions, often associated with prolonged high intensity exercise

Question 33

What are the two theories of muscle cramp origination?

Answer 33

- electrolyte imbalance due to discharge of ACh (little evidence) - motor neurons in spinal cord become hyper excitable resulting in repeated depolarizations

Question 34

What can reduce cramping?

Answer 34

static stretching may reduce through autogenic inhibition

Question 35

What is muscle fatigue?

Answer 35

a decline in a muscle's ability to generate power or force with repeated stimulation or over time

Question 36

What does muscle fatigue cause?

Answer 36

- decrease in force generation -decrease in shortening velocity

Question 37

What are the possible reasons for muscle fatigue?

Answer 37

- alterations in neurotransmitters changing perceptual effort to activate muscle - depletion of glycogen - insufficient oxygen supply - increased acidity - impaired ability to conduct action potential - failure of motor neuron signal propagation

Question 38

How does high intensity exercise produce muscle fatigue?

Answer 38

- accumulation of lactate and other metabolites - depletion of PCr

Question 39

Is recovery from fatigue induced by high intensity exercise fast or slow?

Answer 39

fast

Question 40

How does endurance exercise produce fatigue?

Answer 40

- imbalance in intra and extra-muscular electrolytes and depletion of muscle glycogen

Question 41

How does maximal force apply to adaptions of muscle fatigue?

Answer 41

do not lose as much force if you are stronger

Question 42

How does sub maximal force apply to adaptations of muscle fatigue?

Answer 42

can sustain force for much longer

Question 43

What is mental fatigue?

Answer 43

psychological state caused by prolonged periods of demand cognitive activity and characterized by subjective feelings of tiredness and reduced energy

Question 44

How does mental fatigue affect exercise?

Answer 44

- can decrease motivation and increase perceived exertion, which reduces performance